Taurus' ads always said the newer M85s were rated for +P "for duty use." To me this means a less-than-steady diet, I wouldn't shoot it all the time.

Regular .38s for practice, with enough practice with your defense load to feel comfortable with it.

That's what I always did with my M85s. My oldest one broke after about 1500 rounds--we're talking probably 13-15 years ago--including a fair amount of +P, maybe 400 rounds or so. I started limiting +P a bit more after that one and have had no further issues.